'01 piston slap confirmed

[Georgeandkira]

Hello,  We got practice changing valve cover/spark plug tube gaskets in my friend's 2001 Forester w/86K.  It was encouraging to see how clean the rocker arms were.  The "paired" exhaust valve rockers were interesting to find.  The valve clearances were spot on.  No harm done as the gaskets were hard and leaking a bit already.
         Regarding the use of Subaru's oversize piston in a rehoned cylinder;  if the slap is from one worn cylinder can just one be repaired.  Or is it better to do all 4?  At the moment the advice on Subarus with the ticking sound is to live with  it.  A helpful parts manager in Glenville, NY said he's seen them go for a long time with a tick.  I hope this is one of them.  Kira

[peter32892]

Piston slap and valve ticking are 100% normal on a Subaru with a bit miles on them, it is just part of life with the cars. It might sound bad but the car will be fine.

[skyphix]

Kira,
My '98 Forester has 224,000 miles on it and has been piston slapping as long as the person that owned it before me could remember (they had owned it since new). Different piston design, but you get the point.

My Impreza has one oversized piston in a rehoned cylinder and it runs fine. It still piston slaps, but with 185,000 miles on it you have to expect that. Also, that parts manager knows what he's talking about when it comes to EJ25's. (his name is Fred, and he's on here as well).

[boxersix]

No you cannot have one overbore piston in the motor.  In a nutshell w/o getting technical....the motor will shake itself to destruction. 

Must do all four or none at all as the assembly must remain balanced.  Piston slap is normal in these motors due to the short skirt design of the slugs, even moreso when using forged pistons with larger piston to wall clearances.  I'd run it if all else is fine.